OBJECTIVESTo use the Surveillance, Epidemiology, and End Results (SEER) Database to analyze the impact of postoperative radiation after limb sparing surgery for high-grade extremity soft tissue sarcomas (STS).METHODSWe identified patients, aged 20 to 79, who were diagnosed between 1988 and 2006 with high-grade STS of the extremities and underwent radical limb sparing surgery with or without postoperative external beam radiation. Kaplan-Meier and Cox regression analyses were performed to evaluate the effect of postoperative external beam radiation therapy on overall survival (OS) and disease-specific survival (DSS).RESULTSA total of 983 patients met the selection criteria: 788 (80.2%) received postoperative radiation and 195 (19.8%) underwent surgery alone. For the whole cohort, there were no differences between the groups in OS (P=0.06) or DSS (P=0.20). On subgroup analysis, for tumors ≤5 cm there remained no significant differences in OS (P=0.8) or DSS (P=0.93). However, for tumors >5 cm the 3-year OS improved with the addition of postoperative radiation from 55.6% to 73.4% (P<0.001). Similarly, the 3-year DSS improved from 68.1% to 80.6% (P=0.005).CONCLUSIONSBecause of the retrospective nature of this study and inherent limitations of the SEER database, a large prospective study is needed to further elucidate the relationship between postoperative radiation and survival. However, these data do support the use of adjuvant radiation for patients with high-grade extremity STS measuring >5 cm.